Add a diskimage-builder script that creates an Ubuntu 13.04 image.

Implements: blueprint lang-pack-examples

* Work Item: Define a disk image builder template for a base Ubuntu Python 3.3
system - Ubuntu 13.04 includes cloud-init and python 3.3 so no additional
diskimage-builder elements are needed.

Change-Id: Ib785bc7131b4c9d435dee9289e7fcc68509d195a
Merge "Add a diskimage-builder script that creates an Ubuntu 13.04 image."